speed detection possible improvements:
- refine with 128 sync step instead of 256?
- use bigger initial region (50s) --detect-speed-harder
- use window hann instead of hamming for sync bits (or all bits)?
- remove lrint and QInterpolator?
- detect silence instead of total volume?
- split big region into two smaller ones?
- connected search on even smaller regions?
- reorder memory access in compare to be more cache efficient
- n-best search?
- soft sync?

possible improvements:
- dynamic bit strength

videowmark:
opus length ffprobe -show_format phil.mkv
